1. Field of the Invention
The present invention relates to a display device equipped with a touch panel, which includes a capacitive touch panel, in particular, to a technology effective for preventing an erroneous operation in which a measurement value is lowered to finally disappear occurring in a capacitive touch panel including an air layer provided between a front panel and the touch panel.
2. Description of the Related Art
A display device including a device (hereinafter, also referred to as “touch sensor” or “touch panel”) for inputting information to a display screen by a touch operation (contact and press operation, hereinafter, simply referred to as “touch”) by using a user's finger, a pen, or the like is used for mobile electronic devices such as a PDA and a mobile terminal, various consumer electric appliances, an automated teller machine, and the like. As this kind of touch panel, there are known resistance film type of detecting a change in resistance value of a touched portion, capacitive type of detecting a change in capacitance thereof, optical sensor type of detecting a change in amount of light, and the like.
An exemplary capacitive touch panel is disclosed in Japanese Patent Application Publication No. 2003-511799. In the capacitive touch panel disclosed therein, a vertical detection electrode (X electrode) and a horizontal detection electrode (Y electrode) are arranged in vertical and horizontal two-dimensional matrix, and a capacitance of each electrode is detected by an input processing part. When a conductor such as a finger touches a surface of the touch panel, the capacitance of each electrode increases. Thus, the input processing part detects the increase to calculate input coordinates based on a signal of a capacitance change detected by each electrode.